/// <summary>
/// opengl UI for Cursor.
/// Note: put this as the last one of <see cref="SceneRootUI"/>'s children.
/// </summary>
/// <param name="focalPoint">in percentage(0.00 ~ 1.00).<paramref name="focalPoint"/>.X ranges from 0(left) to 1(right). <paramref name="focalPoint"/>.Y ranges from 0(bottom) to 1(top).</param>
/// <param name="size"></param>
/// <param name="cursorBitmap"></param>
public UICursor(PointF focalPoint,
Size size, string cursorBitmap = "")
: base(AnchorStyles.Left | AnchorStyles.Top,
new Padding(0, 0, 0, 0), size, -Math.Max(size.Width, size.Height), Math.Max(size.Width, size.Height))
{
this.FocalPoint = focalPoint;
TextureRenderer renderer = TextureRenderer.Create(cursorBitmap);
renderer.StateList.Add(new BlendState(BlendingSourceFactor.SourceAlpha, BlendingDestinationFactor.OneMinusSourceAlpha));
this.Renderer = renderer;
}